It's actually Steve Winwood singing it, the one who made the original: http://www.youtube.com/watch?v=cbKNICg-REA&ob=av2e. Of course many people have no idea how many 'new' tracks are just unimaginative crap remixes of old songs. "Stole the synth part from Eric Prydz"? Yeah, if he hadn't stolen- sorry, 'remixed' it from Steve Winwood (who I think is a total prat, incidentally).
Oooh, cool. Thanks for clearing that up. I know dance songs frequently sample vocal parts like that. I just figured something like "call on me" could be something he came up with on his own.
That's like the following:
"http://www.youtube.com/watch?v=0GQjYPWDcmg&ob=av3e'" is the Grammy Award–winning third single taken from Lupe Fiasco's Food & Liquor album and features soul singer Jill Scott and music from Tchaikovsky's Swan Lake, the Danse de Cygnes. The single is based around a sample of "http://www.youtube.com/watch?v=_HsLv4VQvUI" by I Monster, a song that samples "http://www.youtube.com/watch?v=4xNJhqfby-Q" by Gunter Kallman Choir (which in itself is a cover, the http://www.youtube.com/watch?v=2AqR00loT9k.